In the conventional art, as a disposable diaper mainly used in an infant and toddler and the like, there is widely provided so called an open-type disposable diaper provided with a fastening tape for fixing at side flaps of a back waistline portion (or a front waistline portion) thereof. The open-type disposable diaper provided with the above-described fastening tape has been widely used, in particular, in a new-born baby and an infant and toddler because it is easily attachable and detachable.
In the above open-type disposable diaper, there has been known a structure in which a proximal end of a skin contact surface side of the fastening tape is covered by side flaps (nonwoven fabric) more flexible than the fastening tape (for example, Patent Literature 1). According to the above disposable diaper, since the fastening tape prevents the skin of an infant and toddler and the like from being stimulated, it is difficult for the infant and toddler to feel discomfort or pain.